Investigating the Morphology, Optical, and Thermal Properties of Multiphase-TiO2/MAPbI3 Heterogeneous Thin-Films for Solar Cell Applications

The present study evaluates the effect of mesoporous multiphase titanium dioxide (TiO2) nanoparticles (NPs) as an electron transporting layer and investigates the influence of phase composition on the perovskite solar cell (PSC) performances. This study also aims to evaluate PSC performance using conductive silver ink as an alternative counter electrode. The heterogeneous PSC thin-film solar cells were successfully fabricated and assembled by using a simple a doctor blade and two-step spin coating methods under ambient conditions. Scanning electron microscopy (SEM) micrograph images investigate methyl ammonium lead iodide (MAPbI3) crystal formation on the mesoporous TiO2 surface structure. Energy-dispersive x-ray spectroscopy (EDX) spectra reveal excellent qualitative and quantitative analysis corresponding to the SEM images in the TiO2/MAPbI3 heterogeneous thin films. Thermogravimetric analysis (TGA) characterization reveals that the TiO2/MAPbI3 thin films are thermally stable recording a maximum of 15.7% mass loss at 800 °C elevated temperatures. Photoluminescence spectroscopy (PL) characterized the effect of multiphase TiO2 phase transformation on the TiO2/MAPbI3 recombination efficiencies. A maximum of 6% power conversion efficiency (PCE) with the open-circuit voltage (Voc) of 0.58 ± 0.02 V and short circuit current (Jsc) of 3.89 ± 0.17 mAcm−2 was achieved for devices with an active area of 3 × 10−4 m2 demonstrating that the synthesized multiphase TiO2 nanoparticles are promising for large surface area manufacturing. Therefore, it is apparent that multiphase TiO2 NPs play a significant role in the performance of the final device.